1. Field of the Invention
The present invention generally relates to a friction clutch for an internal combustion engine, which friction clutch includes a clutch housing. A crankshaft is fastened to a flywheel, which flywheel has a friction surface. The crankshaft can rotate, with the flywheel, around an axis of rotation. The friction clutch also includes an application plate, which application plate has a friction surface. The application plate is mounted in the clutch housing non-rotationally, but in a manner permitting the application plate to move axially. The friction clutch also has a membrane spring with flexible tabs pointing radially inward to push the application plate toward the flywheel. The membrane spring is supported, on one hand, on the application plate and, on the other hand, on the clutch housing.
The friction clutch further includes a clutch plate, which clutch plate has friction linings. The friction linings can be clamped between the friction surfaces of the flywheel and application plate. The friction clutch has a disengagement system for applying pressure to the flexible tabs. There is also a mechanism to make an automatic adjustment for wear of the friction linings. The mechanism adjusting to the wear of the friction linings includes a ring element, which ring element is concentric with the axis of rotation. The ring element is located between the application plate and membrane spring and the ring element is spring-loaded in the circumferential direction. By means of several oblique or inclined surfaces distributed over the circumference of the ring element, the ring element can maintain an essentially constant distance between the membrane spring and the friction surface of the flywheel.
2. Background Information
Such a friction clutch is disclosed, for example, in German Patent 29 20 932. In such a known friction clutch, the oblique or inclined surfaces are, on one hand, applied directly against the application plate and, on the other hand, against a ring element which is made of sheet metal. The process required to manufacture the oblique surfaces on the application plate is quite complex and expensive, since extensive machining has to be performed.